GitLab

Check return values of various fcntl() invocations in
serialport_config(), serialport_read_nonblock() and
serialport_write_nonblock().

Also, remove some superfluous print conversion specifiers and refine
messages.

Corresponding to flashrom svn r1803.
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>